If not properly treated, type 2 diabetes can lead to complications such as blindness,
kidney failure, heart disease, and nerve damage.

Common symptoms of both type 1 and type 2 diabetes include:

Fatigue, constantly
tired: In diabetes, the body is inefficient and
sometimes unable to use glucose for fuel. The body switches over to
metabolizing fat, partially or completely, as a fuel source. This process
requires the body to use more energy. The end result is feeling fatigued or
constantly tired.

Unexplained weight loss: People with diabetes are
unable to process many of the calories in the foods they eat. Thus, they may
lose weight even though they eat an apparently appropriate or even an excessive
amount of food. Losing sugar and water in the urine and the accompanying
dehydration also contributes to weight loss.

Excessive thirst (polydipsia): A person with diabetes develops high blood sugar levels, which overwhelms the kidney's ability to reabsorb the sugar as the blood is filtered to make urine. Excessive urine is made as the kidney spills the excess sugar. The body tries to counteract this by sending a signal to the brain to dilute the blood, which translates into thirst. The body encourages more water consumption to dilute the high blood sugar back to normal levels and to compensate for the water lost by excessive urination.

Excessive urination (polyuria): Another way the body
tries to rid the body of the extra sugar in the blood is to excrete it in the
urine. This can also lead to dehydration because a large amount of water is
necessary to excrete the sugar.

Excessive eating (polyphagia): If the body is able, it
will secrete more insulin in order to try to manage the excessive blood
sugar levels. Moreover, the body is resistant to the action of insulin in type 2
diabetes. One of the functions of insulin is to stimulate hunger. Therefore,
higher insulin levels lead to increased hunger. Despite increased
caloric intake, the person may gain very little weight and may even lose
weight.

Poor wound healing: High blood sugar levels prevent
white blood cells, which are important in defending the body against bacteria
and also in cleaning up dead tissue and cells, from functioning normally. When
these cells do not function properly,
wounds take much longer to heal and
become infected more frequently. Long-standing diabetes also is associated
with thickening of blood vessels, which prevents good circulation, including the delivery of enough oxygen and other nutrients to body tissues.

Infections: Certain infections, such as
frequent yeast infections of the genitals, skin infections, and frequent
urinary tract infections, may result from suppression of the immune system by
diabetes and by the presence of glucose in the tissues, which allows bacteria
to grow. These infections can also be an indicator of poor blood sugar control in a
person known to have diabetes.

Altered mental status: Agitation, unexplained
irritability, inattention, extreme lethargy, or confusion can all be signs of
very high blood sugar, ketoacidosis, hyperosmolar hyperglycemia nonketotic
syndrome, or hypoglycemia (low sugar). Thus, any of these merit the immediate
attention of a medical professional. Call your health care professional or 911.

Blurry vision: Blurry vision is not specific for diabetes but is frequently present with high blood sugar levels.